Learning Forum

[Alin Ristea]

Hi, I'm trying to do a conjugate heat transfer, where I have a few "cubes" as heat sources (solids) and fluid flow going over them. I have used Ansys for many years and I have done Ansys Discovery conjugate heat transfe for so many times. But this simple simulation is just NOT WORKING. The issue is it is not generating the automatic contacts from the Region Interface Generator. When trying to updated it is inactive. If I change the tolerance it updates but then no contact is generated. The fluid is air, part of a fluid physics reagons, the "cubes" are solids, part of another Thermal Physics Region. I have tried everything over the last few days to solve this mistery, even found a forum on here /forum/forums/topic/region-interface-generator-does-not-generate-interface-between-fluid-solid/ , which actually doesn't solve any problem as nothing from there explanation which was half kept on a private chat doesn't do anything. I have also tried to setup the contact manually, with no result. Does anyone have this problem as I'm beginning to believe this Ansys Discovery license is not capable of solving anythign rather that basic FEA problems!?

 

Thanks in advance,

Alin

[Charudatta Bandgar]

Hey Alin,

What version of Discovery are you using? Can you please confirm if there aren't any interferences between the geometries? 

Please refer to this tutorial for CHT in AIM: Discovery AIM: Getting Started Tutorials - Fluid-Solid Heat Transfer (CHT) Simulation - Ansys Knowledge.

 

Also this is a legacy product of Discovery (discontinued since 2020 release), and now we have a new consolidated Discovery product (latest release 2024R), where you should be able to do the simulation lot more easily. If it is feasible, I would suggest you try this out instead.

Here is the download link for the product:Discovery Downloads - Ansys Knowledge

Here is a CHT course for this product:CHT Analysis in Ansys Discovery | Ansys Courses

 

[Alin Ristea]

Hi Charudatta, thank you for your reply. I'm using  version 2019, as the yearly maintenance and "support" cost was quite high, given Ansys doesn't actually support the product like the other ansys products, but rather the "support" is in a form of an online forum. I can confirm there are no interferences between the geometries, as this is something I have checked a number of times. Thank you for the tutorial link, but this is actually something beyond the basics. What I have found was the issue is caused by the limited capability of Ansys Discovery, which actually cannot have one physics domain included in the other, meaning that my solids cannot be fully immersed into the fluid, which was the real case scenario when the air is flowing over them. Once I have "shaved" off the air volume to match the bottom surfaces of the solids, for which I have added some heat transfer coefficients in convection, this simulation worked easily, as expected, with no issues. I have done this itteratively and reached that conclusion. In regards of your suggestion, does the newer version have this capability? 

A workaround for this would be to have some "connnecting" elements with poor thermal conductivity to the "outside world", going from the solid through the fluid and "outside", which would then make this possible. It did cost me 3 days to find this out, but if I would have had the maintenance up to date, I would have had to spend the same time to find this out :). The initial presentations the resellers do show more what you showed in the above tutorial link, but when you get to real problems like this, that's where the lacking support from Ansys for Discovery would be usually helpful.

[Maria Kenneth]

Exploring the intricacies of conjugate heat transfer can sometimes feel like navigating through a complex virtual conversation, reminiscent of the unpredictable encounters on platforms like omegle. Just as troubleshooting simulation issues requires patience and adaptability, so does engaging with strangers in the vast digital realm.